In a chemical reaction, 300 grams of reactant a are combined with 100 grams of reactant b. both a and b react to completion. how much will the product weigh?

I believe the mass of the product will be 400 grams. This is because according to the law of conservation of mass, mass is neither created nor destroyed . In a closed system, the mass of reactants is equal to mass of products. Therefore, since the total mass of the reactants is 400 grams then the mass of the products will still be 400 grams

OR

200

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j

6.4 cm (max) - 25 cm (min)